1. Technical Field
The present invention relates to a liquid supply unit and the like.
2. Related Art
An inkjet printer has long been known as an example of a liquid ejection apparatus. The inkjet printer can perform printing onto a print medium such as print paper by discharging ink, which is an example of a liquid, from an ejection head to the print medium. It has long been known that the inkjet printer is configured to supply ink stored in a tank, which is an example of a liquid supply unit, to the ejection head. The tank is provided with an ink injection inlet. The user can load ink into the tank from the ink injection inlet. It has long been known that the tank has a configuration in which a liquid containing chamber in which ink is contained and an air containing chamber into which atmospheric air is introduced communicate with each other by a communication portion (see, for example, JP-A-2012-20495). The configuration in which the liquid supply unit is attached to the liquid ejection apparatus is referred to as a liquid ejection system.
In the tank disclosed in JP-A-2012-20495 mentioned above, for example, even if the ink contained in the liquid containing chamber flows out to the air containing chamber side via the communication portion, the ink that has flowed into the air containing chamber can be stored in the air containing chamber. For this reason, with this tank, leakage of the ink contained in the liquid containing chamber to the outside via an atmospheric air opening is easily suppressed. However, if the orientation of the inkjet printer is changed with the ink having flowed into the air containing chamber from the liquid containing chamber, the ink contained in the air containing chamber may flow to the outside of the tank via the atmospheric air opening. To address this, it is considered effective to house a liquid retaining member in the air containing chamber. The liquid retaining member is a member having a high level of ability to absorb and retain a liquid such as ink. The material of the liquid retaining member can be, for example, sponge, sea sponge or the like. By housing the liquid retaining member in the air containing chamber, the ink that has flowed into the air containing chamber from the liquid containing chamber can be retained by the liquid retaining member, and thus the ink is likely to remain in the air containing chamber. However, if the ink that has flowed into the air containing chamber is absorbed by the liquid retaining member, a flow of the atmospheric air may be blocked by the liquid retaining member. In other words, if the ink that has flowed into the air containing chamber is absorbed by the liquid retaining member, entry of the atmospheric air into the liquid containing chamber from the atmospheric air opening may be blocked. If the entry of the atmospheric air into the liquid containing chamber is blocked, along with printing onto a print medium, or in other words, along with consumption of the ink contained in liquid containing chamber, the pressure within the liquid containing chamber becomes lower than the atmospheric pressure. If such a situation occurs, it becomes difficult to supply ink from the tank to the ejection head. In other words, the liquid supply unit of the related art is problematic in that liquid supply may become difficult.